Piston



m T R A M N i PISTON Filed Aug. l2, 1937 INVENTOR JOHN N. MARTIN ATTORNEY Patented Aug. l, l1939 UNITED PATENT oFFlCE 8f Claims.

This invention relates t pump plungers or pistons and particularly to composition packed plungers.

An object of this invention is to provide a plunger adapted to move against high iluid pressures.

Another object is to provide a plunger which is packed with a series of 'spaced composition packing rings, each of Which is individually supported on'the plunger body Without the use o removable spacers or compression nuts.

A specific object is to provide a plunger upon whichthe packingv is spirally arranged, and substantially fluid-tight.

Other objects and advantages of this invention will be apparent from the following detailed description in conjunction With the accompanying dra-wing which illustrates one form of the new invention.

In the drawing:

Figure 1 is an elevation of the plunger of this invention showing the' packing in place.`

Figure 2 is a transverse section taken along line 2 2 of Figure 1.

Figure 3 is a vertical section taken along line 3-3 of Figure 1.

Figure 4 is an elevation of the plunger body with the packing removed.

Figure 5 is a transversel section taken along line line 5 5 of Figure 4. l

Figure 6 is a fragmentary view of a plunger in accordance vvithY this inventionjshowing another arrangement oi packing thereon.

Referring to the drawing, the plunger of this invention comprises a cylindrical' body I00 any suitable metal, having an axial bore II for the passages of fluid therethrough as in the case of the conventional oil vvell pump. Body I0 is reduced in section at each end, the reduced section being threaded externally, as indicated at I2, for attachment to necessary valves'and other pumping equipment. It will be understood that in some cases the reduced ends maybe threaded internally or one end may be threaded internally and the other externally, depending upon the type connection to which theplunger is to be attached; A continuous helical groove I3 is cut into the outside of body IIJ,` the groove being generally square in cross-section. The convolutions ofthe groove are spacedv apart, the metal not removed in the grooving operation forming a continuous helical spacer I4. A continuous coil of compositionfpackingl I5 is mounted in groove I4.

Packing I5 is preferably of such size and shape as to substantially fill groove I3 and to extend radially beyond the edges of spacer I4, in order to t closely Within a-conventional pump cylinder (not shown) Which ordinarily has an internal diameter slightly larger than the external diameter of the plunger body III. With packing I5 arranged in grooves I3 as above described, a continuous helical channel will beformed between the edges of the convolutions of the packing, the bottom of the channel being the outer face of spacer Ill. To` prevent the fluid being pumped from flowing along this channel, notches I6 are cut into spacer I4 and into these notches are inserted packing'segments lll, These segments are cut,V -to iit tightly in notches I6 and to extend radially form body II) 'the same distance as packing` I5, thus making the outer faces of these packing segments flush With the outer or cylinder contacting face, of the main packing I5.

As shown inFigure 4, notches I6 may be cut in each of the convolutions` of spacer I4 and these notches may all be in alignment, rows of such notches being `provided on, opposite sides of plunger body Iil- Figure 6 illustrates an arrangement `or packing, in Which notches` I6 are at differentpoints' along spacer I4 and the corresponding packing segments I'I form a staggered patternbetween theconvolutions of packing I5.

By described arrangementof packing segments I'I a series of dams are lformed between Vthe convolutions of packing I5, thus effectively sealing the channelsbetween these convolutions and preventing the leakage of uid past the plunger when same is in operation.

Groove'lil, is preferably rectangular in cross- Section generally approaching a square, and the packing I5 has a corresponding cross-section, although its thickness, in radial direction With respect to body Iii ,is greater than the depth of groove I3,` thus permitting the packing to protrude beyond the mouth of groove I3 and beyond the outer face of spacer I4. Spacer I4 is also rectangular in rcross-section but is generally narrower than groove I3. For example, groove i3 may be one-quarter inch wide by seven-sixteenths inch deep and packing I5 one-quarter inch square, thus the packing Will protrude one-sixteenth inchoutside groove I3. Spacer I4 will be seven-sixteenthV inches deep by one-eighth inch Wide. Notches I6 will extend entirely through spacer Illgand be of-any suitable depth, preferably the same asgthat of groove I3 and any length, for example one-quarter inch'or more as desired.

In myapplication Serial No. 140,703, led May 4, 1937, I have described a packing arrangement IISl alsV

As in my former application, in this invention each convolution of packing I5 is independently supported by the segment of groove I3in which it is placed. Thus no tightening nuts are re-. quired to hold the packing in place and each con-r`- volution of packing will support a proportional part of the pumping load.V The distortion or wearing out of any convolution of packing I 5 will, therefore, have no appreciable detrimental effect on the remainder of the packing other than to transfer its portion of the total load to the remaining portions of the packing.

rThe spacer I3 maybe formed, as described, by grooving the outer surface of the piston body, or it may be formed by slipping a metal spiral of the proper shape over a smooth cylindrical body and welding orv shrinking, the convolutions thereof on the body to form a rigid bond with the body.

Various 'types of packing may be'used. As

,. noted above,packing having predetermined swelling characteristics may be used, or xed dimension packing may be used and may be pressed into the groove I3 to provide a tight iit therein, and the same applies to packingV segments Il'.

Various changes and vmodifications may be made in the size, shape and form of the elements comprising this invention without departing from the scope of the appended claims.

What I claim and desire tosecure Patent is:

1. A helically packed piston of the class described comprising, a cylindrical piston body, a

helical packing seat on said body, a continuous' helical packing element mounted in said seat in fluid-tight engagement thereinfthroughout lits length, and discontinuous packing elements mounted between adjacent convolutions of said continuousV packing element and adapted to form a/fluidtight seal therebetween, said discontinuous packing elements protruding radially to the outer periphery of said continuous packing element.

scribed comprising, a cylindrical piston body, Ya helical packing seat on said body, a continuous helical packing element constructed of composition material mounted in said seat in duid-tight engagement therein throughout itslength, and discontinuous packing elements constructed of composition material mounted lbetween adjacent convolutions of said continuous packing element and adapted to form a iiuid tight seal therebetween, said discontinuous packing elements protruding radially to the outer periphery of said continuous packing element.

3. A piston comprising a cylindrical body, a packing seat rigidly united with said body and helically arranged thereon in a plurality of spaced convolutions, a continuous composition by Letters,"

2. A helically packed pistony vof the class de-` rbet'ween, spaced notches in said spacer between vadjacent said convolutio-ns, a continuous compo- "sition packing element mounted in said groove in uid-tight engagement therein throughout its length, and segmental composition packing elements mountedY insaid notches and adapted to form a fluid-tight seal between adjacent convolutions of said continuous packing element, said segmental packing elements protruding radially to the outer periphery of said Continous packing element. Y

5. A piston comprising a cylindrical body, a helical groove extending about said body, a continuous composition packing element mounted in said groove in fluid-tight engagement therein throughout itsV length, and discontinuous composition packing elements mounted between adjacent convolutions of said continuous packing element, and adapted to form a duid-tight seal therebetween, said discontinuous packing elements protruding radially to the outer periphery of said continuous packing element.

6. A piston comprising a cylindrical body, a helicalv member rigidly united` with the outer surface of said body and extending laterally therefrom, the convolutions of said member being spaced apart forming a helical groove about said body, a continuous packing element mounted in said groove in Huid-tight engagement therein throughout its length and protruding radially thereof, and discontinuous packing elements` mounted between adjacent convolutions of said packing element and inv Huid-tight engagement therewith, said discontinuous packing elements protruding radially to the outer periphery of said continuous packing element.

'ILA piston comprising'a cylindrical body, av

helical groove extending about 'a portion of said body, a continuous packing' element mounted in said groove in fluid-tightr engagement therein. throughout its entire length, and discontinuous; packing velementsv v'mounted between adjacent;

convolutions of said Y'continuous packing element and in duid-,tight engagement therewith, said discontinuous packing elements protruding radially to the outer periphery of said continuous packing element.

8. A piston comprising'v a cylindrical body, a helical groove extending about a portion of said body, ythe convolutions of y said; groove being spaced apart to provide a helical spacer therebetween, spacednotches in said spacer, a continuous packing Aelement mounted in said groove in Huid-tight engagement therein throughout its Clllength-,and segmental packing elementsmounted in said notches and in fluid-tight engagement with adjacent convolutions of said continuous packing element, said segmental packing velements protruding radially to the outer periphery of 4said continuous packing element.V y n JOHN N. MARTIN.. 

